Safety system for controlling the start-up of elevators

ABSTRACT

A safety system for controlling the start-up of elevators is described for the prevention of the fatal accidents which have recently been occurring due to the lack of care by the personnel responsible and the like who start up the cabin without knowing what is happening inside or even outside it. This has caused death by crushing of dozens of people who are alarmed and try to enter or leave exactly when the cabin begins to move. The system of the present invention does not permit such accidents by not allowing the cabin to move when any door is open, be it the door of the cabin itself or of the floor at which it is stopped.

United States Patent [1 1 Podcameni et' al.

111 3,882,969. 4 1 May 13, 1975 [54] SAFETY SYSTEM FOR CONTROLLING THE START-UP 0F ELEVATORS [76] Inventors: Abelardo Podcameni, Rua

Raimundo Correia 71/801; Aldo Alves Goncalves, Vila Rialma 156/101; Sebastiao' Kirk, Av. Atlantica 478/308, all of Rio de Janeiro, Brazil [22] Filed: June 14, 1973 [21] Appl. No.: 370,186

[30] Foreign Application Priority Data 02 L I DISCRIMINATOR 1,934,500 11/1933 Hearn et a1. 187/29 X 2,111,459 3/1938 Molander 187/29 Primary ExaminerRobert K. Schaefer Assistant Examiner-W. E. Duncanson, Jr. Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A safety system for controlling the start-up of elevators is described for the prevention of the fatal accidents which have recently been occurring due to the lack of care by the personnel responsible and the like who start up the cabin without knowing what is happening inside or even outside it. This has caused death by crushing of dozens of people who are alarmed and try to enter or leave exactly when the cabin begins to move. The system of the present invention does not permit such accidents by not allowing the cabin to move when any door is open, be it the door of the cabin itself or of the floor at which it is stopped.

6 Claims, 1 Drawing Figure l 2\ SIGNAL I SOURCE I 6 t- 7 CONTROL 1 cmcun SAFETY SYSTEM FOR CONTROLLING THE START-UP OF ELEVATORS The present invention refers to a safety system for installation in elevators. Its object is to protect the users from accidental crushing and from falling into the well. It operates to prevent the start-up of the cabin if any door is open or unlocked. If the safety system is damaged, tampered with or short-circuited on purpose or by accident, the elevator will still remain stationary just as it will if manual actuation is attempted for startingup the elevatorfrom the engine room when any door is open or unlocked. This is the novelty characterizing and distinguishing the present invention and by which a. a lock which is the fixed part and independent of the door and b. a latch which is the part integral with the door. In the present invention a feed line having an electric signal of a given type and value is connected to the lock. Within or integral with the latch there is an electric circuit capable of modifying the nature and/or the value of the signal from the source of supply. When the lock and the latch are mechanically coupled there is also an electrical coupling. By means of adequate electrical contacts which are insulated from the metallic masses of the lock and the latch, the supply signal is transmitted to the latch, modified and returned to the,

lock. The modified signal is then transmitted along the line independent of all the others to the engine room and introduced into a discriminator. The discriminator is a circuit capable of recognizing the signal, duly modifled by the action of the circuit in the latch and only capable of operting when it receives this signal at its input.

During operation the discriminator supplies an output logic signal. Thus the line from each lock is led to its respective discriminator in the engine room. The outputs of all the discriminators are connected to a coupling circuit which carries out an AND logic function, that is: there is a logic output signal only when there is a signal at all of the inputs. This signal operates a control switch which serves for switching the lines from the direction switch to the drive motor and also those going from the brake operator (if there is one) to the service brake. The manual operation of the control switch cannot be effected by unqualified personnel since the control switch, the discriminators and the coupling circuit are maintained within a locked metallic box. The demand wiring to and from the metallic box passes within metallic conduits. The terminal box of the motor is sealed.

The short-circuiting of a lock-line makes the signal from the supply source pass to the lock-line and to the input of the discriminator without modification whereby the discriminator does not operate.

It should be observed that the modification of an electrical signal from a supply source can also be made by placing a circuit in parallel with the discriminator input, that is: a part of the signal from the supply source is always present at the discriminator input until the moment when said circuit is placed in parallel with the discriminator input and the nature and/or value of that part of the signal, previously present, is modified and the discriminator operates. This arrangement has the advantage of making the metallic mass of the lock and latch electrical conductors (ground line or neutral line). Regarding the installation of the system, it is possible to modify the prior art electro-mechanical lock or simply to add another working in the manner described. The modification to be made in the original elevator installation in the engine room is only in the direction switch connections to themotor and those from the brake operator to the brake which instead of going directly pass through the control switch of the safety system. A duly qualified mechanic can start-up the elevator with the door open since he will have a tool which simulates the latch, this tool having in its interior the same latch circuit and adequate connections.

Still from the practical point of view, since all the discriminators are logic output circuits, that is to say, when operating or not, the discriminators are also used for switching on small lamps placed on the outside of said metallic box for indicating if a door, and which door, is unlocked: these are door monitors. Other lamps are energized in correspondence with the operation of the coupling and control circuits: these are function monitors. In parallel with the elements of the control switch, lamps will light if the direction switch is actuated when the control switch is inoperative: these are fault monitors. In the logic dependency between the coupling signal and the control switch operation there is another fault monitor which indicates when only one of these elements is operating. The above more sophisticated version facilitates maintenance of the apparatus as well as indicates whether there is a fault or not in the safety system.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawing which is a block diagram of the circuit according to the present invention.

Referring now to the FIGURE, blocks L L L represent the latches of the elevator doors on each floor of a building. The latches represented by the blocks are preferably those fixed to the doors themselves rather than to the door posts. Each latch is a suitable mechanical latch which may also electrically control the operation of the elevator motor. Thus each latch includes a device 1 which is placed in circuit only when the elevator door on that floor is closed. The device 1 comprises any suitable element or combination of elements for modifying the signal on input line 1 from a source 2. This device may be, for example, a Zener diode for altering the signal amplitude, a resistor for modifying the current, a transformer for modifying the polarity, a capacitor for modifying the phase or a combination of such elements for modifying the RMS valve of the signal from the source 2.

When the doors are open the electrical signal leaving each latch L to L, is identical to the signal on line I. When a door is closed the device 1 will be introduced into the circuit in the corresponding latch L, L, whereby the signal on the corresponding output line 3 3,, passes disponding discriminator D D Each discriminator gives an output to a logic AND circuit determined by the nature of the signal on corresponding line 3 3 The AND circuit is arranged to give an output when all the latches L Y. L, are closed, that is to say when there is a modified signal on each of the lines 3 3 This output from AND circuit 4 controls a main control switch 5 in such a way that switch 5 is closed only when all latches L to L are closed.

Switch 5 is in circuit with the elevator motor and brake whose operations are all controlled by the conventional control circuit 7. The control lines from circuit 7 pass in the form of a cable to the input side of switch 5 whereby no control can be effective with respect to the motor and brake 6 unless switch 5 is closed. A

The discriminators, the logic AND and switch 5 are all contained within a closed metal box 8 and the cables leading from control 7 to the interior of box 8 to switch 5 and leaving box 8 from switch 5 to the motor and brake 6 are contained in metallic protective conduits;

Each discriminator D D is connected to an indicator panel 9 on the outside of box 8 including individual lamps which only light when a corresponding door is opened. These lamps serve to indicate when there is a fault in any of the discriminators. A further panel 10 having two indicator lamps on the outside of box 8 is connected to AND circuit 4 one of the lights being energized only when a door is open and the other being energized when all the doors are closed. The two panels 9 and 10 serve to detect errors in the discriminators or the logic circuit.

As can be seen from the above the invention refers to a new and original system which has industrial use and is efficient, reliable, useful and practical, it being understood that many modifications may be made within the scope of the invention as defined in the following claims.

What is claimed is:

1. In an elevator system including a vertical shaft extending through a plurality of building floors and hav-v ing a shaft opening at each floor to permit passenger access, door means at each floor for closing the respective shaft openings, an elevator cab suspended in the shaft for bidirectional vertical movement therein, control means, and drive motor/brake means for moving the cab in response to the'control means, an improved. safety circuit comprising:

a. a plurality of electro-mechanical lock means individually and operatively associated with each door means,

b. means for supplying an electrical signal to each of the lock means, the same signal beingsupplied to each of the lock means and said signal having substantially constant identifying characteristics,

c. a plurality of signal modification means individually included in each lock means for modifying at least one of the signal identifying characteristics in response to the closure of the associated door means, and

d. means for detecting the modification of all of the electrical signals and for enabling the operation of the drive motor/brake means in response thereto.

2. A safety circuit as defined in claim 1 wherein the means for detecting comprises a plurality of discriminators individually coupled to the signal modification means, and an AND circuit having its inputs coupled to the discriminator outputs.

3. A safety circuit as described in claim 2 wherein the means for enabling comprises a switch connected in series in the circuit of the drive motor/brake means and operable to complete said circuit in response to anoutput from the AND circuit.

4. A safety circuit as described in claim 3 wherein the electrical signal is also supplied to each of the discriminators.

5. A safety circuit as described in claim 3 wherein the means for supplying an electrical signal, the discriminators, the AND circuit, and the switch are all mounted and contained within a secure metallic housing located in an engine room of the elevator system.

6. A safety circuit as described in claim 3 further comprising a first indicator panel having a plurality of lights individually connected to the discriminators for indicating when an associated door means is opened, and a second indicator panel having two lights connected to the AND circuit for indicating when any one of the door means is opened and when all of the door means are closed. 

1. In an elevator system including a vertical shaft extending through a plurality of building floors and having a shaft opening at each floor to permit passenger access, door means at each floor for closing the respective shaft openings, an elevator cab suspended in the shaft for bidirectional vertical movement therein, control means, and drive motor/brake means for moving the cab in response to the control means, an improved safety circuit comprising: a. a plurality of electro-mechanical lock means individually and operatively associated with each door means, b. means for supplying an electrical signal to each of the lock means, the same signal being supplied to each of the lock means and said signal having substantially constant identifying characteristics, c. a plurality of signal modification means individually included in each lock means for modifying at least one of the signal identifying characteristics in response to the closure of the associated door means, and d. means for detecting the modification of all of the electrical signals and for enabling the operation of the drive motor/brake means in response thereto.
 2. A safety circuit as defined in claim 1 wherein the means for detecting comprises a plurality of discriminators individually coupled to the signal modification means, and an AND circuit having its inputs coupled to the discriminator outputs.
 3. A safety circuit as described in claim 2 wherein the means for enabling cOmprises a switch connected in series in the circuit of the drive motor/brake means and operable to complete said circuit in response to an output from the AND circuit.
 4. A safety circuit as described in claim 3 wherein the electrical signal is also supplied to each of the discriminators.
 5. A safety circuit as described in claim 3 wherein the means for supplying an electrical signal, the discriminators, the AND circuit, and the switch are all mounted and contained within a secure metallic housing located in an engine room of the elevator system.
 6. A safety circuit as described in claim 3 further comprising a first indicator panel having a plurality of lights individually connected to the discriminators for indicating when an associated door means is opened, and a second indicator panel having two lights connected to the AND circuit for indicating when any one of the door means is opened and when all of the door means are closed. 